Devices that use radio frequencies (RF) are highly regulated by the government authorities, such as the Federal Communications Commission (FCC) in the United States, to ensure that the wireless spectrum may be shared by multiple private and government entities without interfering with each other. Depending on the specific frequency bands, the FCC will require standards associated with one or more of output power, harmonics, occupied bandwidth, as well as confirming the intended function and application of the device are compliant, for example.
Transmitters may operate at different frequencies, depending on the availability of frequency bands that are relatively free of interference. The antenna for a transmitter or transceiver operating in a particular frequency band typically has a length approximately equal to one-quarter of the wavelength of the transmission frequency. In order to comply with government regulations, manufacturers design several variants of the same product having different hard wired antennas depending on the RF requirements of a particular location or application. The antennas may also be subject to damage during manufacture or installation of equipment in which the antennas are installed, thus affecting performance of the antennas and creating another difficulty for manufacturers.
Traditional luminaires can be turned ON and OFF, and in some cases may be dimmed, usually in response to user activation of a relatively simple input device connected to lines supplying power to the luminaires. Often traditional luminaires are controlled individually or as relatively small groups at separate locations. More sophisticated lighting control systems automate the operation of the luminaires throughout a building or residence based upon preset time schedules, occupancy, and/or daylight sensing. Such lighting control systems receive sensor signals at a central lighting control panel, which responds to the received signals by deciding which, if any, relays, switching devices, and/or dimming ballasts to drive in order to turn on or off and/or adjust the light levels of one or more luminaires. More recently, lighting control systems have begun to utilize wireless communications in support of monitoring and luminaire control operations. Migration to wireless communication, however, raises implications regarding the requirements of radio frequency operations such as those outlined above, for example, how best to implement antennas optimized for communication on a particular frequency band in a manner suitable for implementation in a lighting system.
Thus, there is a need for improved antenna configurations, particularly that may be suitable for use in control devices of or lighting fixtures or in other wireless intelligent lighting system elements that rely on the use of the antennas for wireless lighting system communications.